CN110501178B

CN110501178B - Comprehensive performance detection system and reliability test method for numerical control rotary table

Info

Publication number: CN110501178B
Application number: CN201910814354.2A
Authority: CN
Inventors: 何佳龙; 赵新跃; 王继利; 朱晓翠; 王伟; 李国发; 杨兆军; 陈传海; 王彦鹍; 罗巍
Original assignee: Jilin University
Current assignee: Jilin University
Priority date: 2019-08-30
Filing date: 2019-08-30
Publication date: 2021-03-26
Anticipated expiration: 2039-08-30
Also published as: CN110501178A

Abstract

The invention discloses a comprehensive performance detection system and a reliability test method for a numerical control rotary table, which comprises the following steps: the device comprises a noise detection part, a positioning detection part, a vibration detection part, an oil pressure detection part, a turntable motor voltage detection part, a turntable motor current detection part and a signal processing unit. The invention also discloses a reliability test method of the numerical control rotary table, which is a method carried out on the basis of the original reliability test bed of the numerical control rotary table and the comprehensive performance detection system and comprises the parts of determination of product reliability evaluation indexes, determination of sampling quantity and test time, reliability test of the numerical control rotary table, fault judgment and data recording, data processing, reliability modeling and the like. The system can detect comprehensive performance parameters such as oil pressure, noise, vibration, positioning precision, repeated positioning precision, current and voltage of a rotary table motor and the like of the numerical control rotary table, and develop a reliability test method with simulated actual working condition loading.

Description

Comprehensive performance detection system and reliability test method for numerical control rotary table

Technical Field

The invention belongs to the field of physical measuring instruments; in particular to a comprehensive performance detection system and a reliability test method for a numerical control rotary table.

Background

The development trend of high speed, high precision and modularization of numerical control machine tools is gradually remarkable as important basic equipment of modern manufacturing technology. At present, the domestic numerical control machine tool still has a large gap with the foreign advanced level in the aspects of reliability level, processing precision, processing dynamic performance and the like, becomes the technical bottleneck of industrial development, and is extremely unfavorable for the exciting high-end equipment manufacturing industry in China and gradually getting rid of monopoly and market erosion of the foreign high-end numerical control machine tool. The numerical control rotary worktable is one of core functional components of a numerical control machine tool, and the precision retentivity, the vibration resistance and the reliability level of the numerical control machine tool directly influence the precision index of a machined part and the reliability level of the whole numerical control machine tool under actual machining conditions. Therefore, the reliability test of the numerical control rotary table is carried out under the simulation of the actual working condition, and the detection, monitoring and analysis processing of the comprehensive performance parameter index are carried out, so that the method has important practical application significance.

At present, the reliability test research of key functional parts of the numerical control machine tool in China is still relatively few, and a definite and complete reliability test method and specification of the numerical control rotary table are not used as guidance; meanwhile, the performance parameters of the numerical control rotary table are detected only once and are mostly measured by static characteristics, the dynamic characteristics of the numerical control rotary table loaded under the simulated actual working condition are not deeply known, and the evaluation of the performance parameters of the numerical control rotary table and the accuracy and effectiveness of a reliability test are seriously influenced.

Disclosure of Invention

The invention aims to solve the problems and provides a comprehensive performance detection system of a numerical control rotary table.

A kind of numerical control rotary table comprehensive properties detecting system, it includes: noise detection portion 2, positioning detection portion 3, vibration detection portion 4, oil pressure detection portion 5, turntable motor voltage detection portion 6, turntable motor current detection portion 7, signal processing unit: the method is characterized in that: the signal processing unit includes: a signal amplifier 81, a signal acquisition output device 82 and an upper server 83; the signal amplifier 81 is connected with the signal acquisition output device 82 through a cable; the signal acquisition output equipment 82 is connected with an upper server 83 through a cable;

the noise detection section 2 includes: a noise sensor 21, a first magnetic base 22; the connecting rod of the noise sensor 21 is fixedly connected with the first magnetic base 22; the noise sensor 21 is connected to the signal amplifier 81 through a cable;

the positioning detecting section 3 is a laser interferometer including: a laser head 31, an angle interference mirror 32, a third magnetic base 33, a reflecting mirror 34 and a second magnetic base 35; a fixing bracket 311 is arranged below the laser head 31; the angle interference mirror 32 is fixed on a third magnetic base 33; the reflector 34 is fixed on the second magnetic base 35; the laser head 31 is provided with a data transmission end; the data transmission end of the laser head 31 is connected with the signal amplifier 81;

the vibration detecting section 4 is an acceleration sensor; the acceleration sensor is provided with a connecting seat and a vibration signal output end; the vibration signal output end is connected with the signal amplifier 81 through a cable;

the oil pressure detecting portion 5 includes: a connecting three-way pipe 51 and an oil pressure sensor 52; the connecting tee 51 is a metal standard; the connecting three-way pipe 51 is provided with a testing connecting pipe orifice, an oil outlet pipe connecting pipe orifice and a sensor connecting pipe orifice; the sensor connecting pipe orifice is connected with an oil pressure sensor 52; the oil pressure sensor 52 is provided with an oil pressure detection signal output end; the oil pressure detection signal output end is connected with a signal amplifier 81;

the turntable motor voltage detecting section 6 includes: a voltage transformer and a voltage transmitter; the voltage transformer is connected with the voltage transmitter; the voltage transmitter is connected with the signal amplifier 81;

the turntable motor current detection section 7 includes: a current transformer and a current transformer; the current transformer is connected with the current transformer; the voltage transmitter is connected to a signal amplifier 81.

Permanent magnets are arranged in connecting seats at the lower ends of the first magnetic base 22, the second magnetic base 33 and the third magnetic base 35.

The turntable motor voltage detecting section 6 includes: a voltage transformer and a voltage transmitter; the voltage transformer is divided into: an A-phase voltage transformer PT1, a B-phase voltage transformer PT2 and a C-phase voltage transformer PT 3;

the primary side of the A-phase voltage transformer PT1 is provided with a primary side voltage detection connecting end IM 1, a primary side output end IN 1, a secondary side access end IM 1 and a secondary side output end IN 1;

a primary side voltage detection connecting end IIM 2, a primary side output end IIN 2, a secondary side access end IIm 2 and a secondary side output end IIn 2 are arranged on the primary side of the B phase voltage transformer PT 2;

a primary side voltage detection connecting end III M3, a primary side output end III N3, a secondary side access end III M3 and a secondary side output end III N3 are arranged on the primary side of the C-phase voltage transformer PT 3;

the voltage transformer is divided into: an A-phase voltage transmitter XT1, a B-phase voltage transmitter XT2 and a C-phase voltage transmitter XT 3;

the A-phase voltage transmitter XT1 is provided with a first voltage transmitter access end, a first voltage transmitter grounding end and a first voltage transmitter signal output end; the first voltage transmitter access end is connected with a secondary side access end I m 1;

the phase B voltage transmitter XT2 is provided with a second voltage transmitter access end, a second voltage transmitter grounding end and a second voltage transmitter signal output end; the second voltage transmitter access end is connected with a secondary side access end IIm 2;

the C-phase voltage transmitter XT3 is provided with a third voltage transmitter access end, a third voltage transmitter grounding end and a third voltage transmitter signal output end; the third voltage transmitter access end is connected with a secondary side access end IIIm 3;

the primary side output end IN 1, the primary side output end IIN 2, the primary side output end IIIN 3, the secondary side output end IN 1, the secondary side output end IIn 2, the secondary side output end IIIn 3, the first voltage transmitter grounding end, the second voltage transmitter grounding end and the third voltage transmitter grounding end are in collinear grounding; the signal output end of the first voltage transmitter, the signal output end of the second voltage transmitter and the signal output end of the third voltage transmitter are connected with the signal amplifier 81 through cables;

the turntable motor current detection section 7 includes: a current transformer and a current transformer;

the current transformer is a clamp type current transformer; it includes: a phase current transformer CT1, a phase current transformer CT2 and a phase current transformer CT 3;

the A-phase current transformer CT1 is provided with a first current transformer connecting end and a first current transformer grounding end;

the B-phase current transformer CT2 is provided with a second current transformer connecting end and a second current transformer grounding end;

the C-phase current transformer CT3 is provided with a third current transformer connecting end and a third current transformer grounding end;

an a-phase current converter IT1, a B-phase current converter IT2, a B-phase current converter IT 3;

the A-phase current transformer IT1 is provided with a first current transformer connecting end, a first current transformer grounding end and a first current transformer signal output end;

the B-phase current transformer IT2 is provided with a second current transformer connecting end, a second current transformer grounding end and a second current transformer signal output end;

the C-phase current transformer IT3 is provided with a third current transformer connecting end, a third current transformer grounding end and a third current transformer signal output end;

the first current transformer connecting end is connected with the first current transducer connecting end through a cable; the connecting end of the second current transformer is connected with the connecting end of the second current transducer through a cable; the connecting end of the third current transformer is connected with the connecting end of the third current transducer through a cable; the grounding end of the first current transformer, the grounding end of the second current transformer, the grounding end of the third current transformer, the grounding end of the first current sending changer, the grounding end of the second current sending changer and the grounding end of the third current sending changer are in collinear grounding;

the first current transformer signal output terminal, the second current transformer signal output terminal, and the third current transformer signal output terminal are connected to the signal amplifier 81 through cables.

During the noise detection and test measurement, the numerical control rotary table 12 rotates by an interval angle d along the clockwise direction, and the recorded angle reading a1 is the detection starting point; rotating the numerical control rotary table 12 by an angle 2d in the counterclockwise direction, and recording an angle reading b 1; the above step is repeated m =360/d times, i.e. the measurement is completed 1 turn counter clockwise, and the angle readings a1, a2, …, am and b1, b2, …, bm are recorded. Measuring n circles according to the method;

the clockwise measurement method is the same as the counter-clockwise measurement method described above;

the upper computer calculates the error value of each detection interval relative to the detection starting point according to the provisions of the numerical control machine detection standard GB-17421.2-2000, and then calculates the rotation positioning precision and the repeated positioning precision of the numerical control rotary table 12 according to the standard.

The invention also aims to provide a reliability test method for the numerical control rotary table.

A reliability test method for a numerical control rotary table adopts the comprehensive performance detection system for the numerical control rotary table and is operated according to the following steps:

1. preparation conditions for reliability test

1) And (3) test environment: the reliability test has the environmental temperature of +15 to +35 ℃ (290K to 308K), the working pressure of 187V to 242V, the relative humidity of 45 to 75 percent and the atmospheric pressure of 86 to 106 kPa; the test must be performed under defined environmental conditions;

2) test samples: the test samples in the reliability test provided by the invention all have qualified performance and functions, the test samples which leave the factory are proved to be qualified by factory inspection, the test samples are new products or products produced under the condition of meeting normal production, and the test samples are used according to the normal use working condition, and all the test samples are numbered before the test;

3) the test device comprises: the test equipment, the detection instrument and the instrument for the reliability test meet the relevant requirements, and the test device of the numerical control rotary table is required to be installed and debugged according to the regulations before the test;

4) the test personnel: a specially assigned person is responsible for organization and facilities of the reliability laboratory test of the numerical control rotary table, and the responsibility of testers, maintainers and fault analysis personnel, duty arrangement, test diary, fault maintenance and the like are determined to be ready;

2. determining reliability evaluation index

Firstly, determining a reasonable reliability evaluation index; the Mean Time Between Failures (MTBF) reflects the time quality of the product and reflects the capability of the product to keep functions within the specified time; the mean time to first failure MTTFF reflects the mean working time before the first failure of the product; the mean repair time MTTR reflects the mean repair time when the product is in a working state of transposition from a fault state; considering that the numerical control rotary table is a repairable complex electromechanical product, and is used as one of key functional parts of the numerical control machine tool, the numerical control rotary table needs to have higher reliability level and stronger fault repairing performance;

the reliability test method of the numerical control rotary worktable selects the mean fault interval working time MTBF, the mean first fault time MTTFF and the mean repair time MTTR as main reliability evaluation indexes; during actual test, adding other reliability indexes (such as reliability degree and the like) as references for evaluating the reliability level of the numerical control rotary table according to the requirements of users;

3. determining the number of samples and the test time

1) Sampling scheme

Randomly extracting samples from qualified numerical control rotary table products, wherein the samples are not allowed to be subjected to any special treatment in quality; if the early fault elimination test is carried out, the whole number test is adopted; if a reliability bench test is carried out, the number of samples is determined according to the annual output which is less than or equal to 10 and is 1-2, the annual output which is 10-100 and is 3-5, the annual output which is more than 100 and is 5 percent, and the total number of general samples does not exceed 10.

2) Test time

The selected test time is 3 times or more than that of the MTBF of the existing numerical control rotary table; when the early fault elimination test is carried out on the numerical control rotary table, the total test time is not less than 120 hours;

4. comprehensive performance detection of numerical control rotary worktable

According to the detection method of the comprehensive performance detection system of the numerical control rotary table provided by the embodiment 2, the comprehensive performance detection such as noise detection, positioning detection, vibration detection, oil pressure detection, motor voltage detection, motor current detection and the like is respectively carried out on the numerical control rotary table, and the specific numerical value or range of each performance parameter of the numerical control rotary table is recorded in detail.

5. Reliability test of numerical control rotary table

1) Turntable no-load transposition test

The no-load indexing test needs to take into account the angular interval of indexing and the test time. The accumulated test time of the no-load transposition test of the numerical control rotary worktable accounts for about 10 percent of the total test time;

in the no-load transposition test process, the comprehensive performance detection such as noise detection, vibration detection, motor voltage detection, motor current detection and the like needs to be carried out on the numerical control rotary table.

Carrying out no-load transposition test on the numerical control rotary table according to the following steps:

a. checking the lubricating and cooling states of the test bed of the numerical control rotary table and the numerical control rotary table;

b. installing a chuck specified in design on the working table surface of the numerical control rotary working table, and clamping a workpiece of which the shape and the size meet the bearing requirements of the numerical control rotary working table;

c. starting a test, and carrying out forward and reverse continuous sequential transposition of the brake mechanism loosening, transposition and locking by the numerical control rotary worktable according to the following angle intervals and sequence;

a) spaced 0 ° 5 ° 10 ° 15 ° 20 ° … … 345 ° 350 ° 355 ° 360 ° 355 ° 350 ° 345 ° … … 20 ° 15 ° 10 ° 5 ° 0 °;

b)0° 10° 20° 30°……330° 340° 350° 360° 350° 340° 330°……40° 30° 20° 10° 0°；

c)0° 30° 60° 90° 120°……270° 300° 330° 360° 330° 300° 270°……90° 60° 30° 0°；

d)0° 60° 120° 180° 240° 300° 360° 300° 240° 180° 120° 60° 0°；

2) dynamic force loading test of turntable at rest

The amplitude, the mean value, the angle and the frequency of the dynamic force loading are divided into 2 large groups, each large group can be divided into 4 small groups of 6Hz, 15Hz, 21Hz and 35Hz according to the loading frequency, and the proportion of the dynamic force cycle number loaded by each small group is shown in tables 3 and 4; the accumulated test time of the dynamic force loading test when the numerical control rotary table is static is not less than 30% of the total test time;

in the dynamic force loading test process when the rotary table is static, the comprehensive performance detection such as noise detection, motor voltage detection, motor current detection and the like needs to be carried out on the numerical control rotary table.

The dynamic force loading test of the turntable when the turntable is static is carried out according to the following steps:

c. starting a test, operating the numerical control rotary table to 0 degree and locking, then loading the numerical control rotary table in an electro-hydraulic servo loading mode according to the loading schemes of the tables 3 and 4, and avoiding impact when applying dynamic force; before changing the loading angle or frequency, the numerical control rotary table needs to be controlled to rotate 45 degrees in sequence, and then loading is carried out;

tables 3 and 4 are eight-order program loading spectra of the numerically controlled rotary table at different loading angles and loading frequencies, respectively.

3) Dynamic force loading test during operation of rotary table

The amplitude, mean value, angle and frequency scheme of the dynamic cutting force of the simulation loading is the same as that of the dynamic force loading test when the rotary table is static. The numerical control rotary table in the dynamic force loading test during the operation of the rotary table needs to continuously operate at the rotating speed of 5-10 r/min, and the accumulated test time of the dynamic force loading test during the operation of the numerical control rotary table accounts for not less than 50% of the total test time;

c. and starting a test, controlling the numerical control rotary table to continuously run at a rotating speed of 5-10 r/min, and then carrying out dynamic force loading on the numerical control rotary table in an electro-hydraulic servo loading mode according to the loading schemes in the tables 3 and 4, wherein impact is avoided when dynamic force is applied. Before changing the loading angle or frequency, the numerical control rotary table needs to be controlled to rotate 45 degrees in sequence, and then loading is carried out;

6. comprehensive performance detection of numerical control rotary worktable

According to the detection method of the comprehensive performance detection system of the numerical control rotary table provided in embodiment 2, comprehensive performance detection such as noise detection, positioning detection, vibration detection, oil pressure detection, motor voltage detection, motor current detection and the like is respectively performed on the numerical control rotary table, specific values or ranges of each performance parameter of the numerical control rotary table are recorded in detail, and comparison analysis is performed on each performance parameter of the numerical control rotary table detected in the previous (step 4).

7. Failure determination and data recording

1) Failure determination

In the reliability test process of the numerical control rotary table, any one of the following events is judged to be a fault:

a. the numerical control rotary table or a part of the numerical control rotary table loses one or more functions;

b. the performance parameters of the numerical control rotary worktable or a part of the performance parameters thereof exceed the allowable range in the technical conditions of the product;

c. loosening, breaking and damaging states of parts, structural members or components of the numerical control rotary worktable occur;

2) data recording

During the reliability test period of the numerical control rotary worktable, data should be effectively collected, analyzed and maintenance and change measures should be recorded in time. The recording of the content should include: numbering a numerical control rotary table; the start of the test period; time and test conditions of the occurrence of the fault; a fault phenomenon; the cause of the failure; classifying faults; corrective action taken; accumulating the test time and times; signing by a test attendant; maintenance time; filling a reliability operation record table and a reliability laboratory test fault record table of the numerical control rotary table;

8. data processing and reliability modeling

1) Reliability evaluation index observed value calculation

Assuming that N is the number of test samples of the numerical control rotary table, mi is the accumulated working time of the ith numerical control rotary table, ri is the accumulated fault number of the ith numerical control rotary table, and N is the accumulated fault total number of the numerical control rotary table, the observation value of the mean fault interval working time MTBF is as follows:

the observed value of the mean time to first failure MTTFF is:

in the formula: mi is the working time before the first fault of the ith numerical control rotary working table;

the observed values for mean time to repair MTTR are:

in the formula:m _Rjis as followsjAccumulated repair time of the numerical control rotary worktable;r _jfirst, thejAnd (4) accumulating the fault number of the numerical control rotary working table.

2) Reliability modeling

And (4) taking the objective function as the mean fault interval working time MTBF to explain the reliability modeling process. The continuous non-fault working time of the numerical control rotary worktable is counted through data processingT _iCalculating a reliability function R (t) Fault rate functionλ(t) Mean Time Between Failure (MTBF); fitting a fault probability density function curve using a two parameter Weibull distributionf(t) Carrying out parameter solution through a simulated annealing algorithm, and carrying out K-S inspection on the obtained distribution model so as to determine the distribution rule of the objective function;

the method comprises the following specific steps:

a. calculating reliability function R (of numerical control rotary table)t) And fault rate functionλ(t):

In the formula, cumulative faultsProbability function F: (t)=1-R(t)；

b. Calculating Mean Time Between Failures (MTBF):

the probability density function of the two-parameter weibull distribution is:

in the formula (I), the compound is shown in the specification,θin order to be a scale parameter,βis a shape parameter;

d. performing K-S test on the target function distribution model, and if the test statistic Dn value is smaller than a critical value Dn, a, accepting the original hypothesis; otherwise, rejecting; and further obtaining the distribution rule of the target function.

Compared with the prior art, the invention has the beneficial effects that:

1. for the detection of the performance parameters of the numerical control rotary table, the performance parameter detection device and the detection method of the existing literature are single, or the detection is only carried out when the numerical control rotary table is in a static state or in idle running. The comprehensive performance parameters of the numerical control rotary worktable can be detected, and the running state, the health state, the precision and the reliability level of the numerical control rotary worktable can be comprehensively evaluated and known; meanwhile, the invention can also carry out comprehensive performance detection on the numerical control rotary table under the condition of simulating different actual working conditions, can detect the performance parameters of the numerical control rotary table according to the actual working condition conditions of users, provides more real data for carrying out researches such as precision retentivity, reliability evaluation and the like of the numerical control rotary table, and has practical application significance compared with performance parameter detection carried out during static or idle running.

2. At present, a complete reliability test method for a numerical control rotary table is not available. The reliability test method of the numerical control rotary working table is based on the reliability test table of the numerical control rotary working table and the comprehensive performance detection system, the reliability test method of the numerical control rotary working table covers all working modes of the numerical control rotary working table through three test modes of a continuous transposition test, a dynamic force loading test when a rotary table is static, a dynamic force loading test when the rotary table runs and the like, and meanwhile, the dynamic force loading mode is adopted to simulate an actual cutting load, so that the reliability test of the numerical control rotary working can be carried out under the simulation of various different working conditions and different working modes.

3. According to the dynamic force loading scheme in the dynamic force loading test when the rotary table is static and the dynamic force loading test when the rotary table runs, dynamic cutting loads of the numerical control rotary table under different cutting process parameters can be simulated by using an eight-order program loading spectrum, the dynamic force is simulated and loaded by the reliability test bed of the numerical control rotary table, the reliability test efficiency of the numerical control rotary table is improved, and potential faults of the numerical control rotary table can be effectively excited and exposed.

4. The reliability test method for the numerical control rotary working table is innovatively integrated with a comprehensive performance detection method for the numerical control rotary working table, and can detect/monitor the decline/change process and the performance/precision fault of the performance parameters of the numerical control rotary working table in the reliability test process of the numerical control rotary working table, so that the performance/precision fault can be fully considered in the reliability evaluation process, and the reliability evaluation accuracy of the numerical control rotary working table is improved.

Drawings

FIG. 1 is an axial projection view of the system for detecting the comprehensive performance of a numerical control rotary table according to the present invention;

FIG. 2 is a disassembled axial projection view of the noise detection part of the numerically controlled rotary table of the system for detecting the comprehensive performance of the numerically controlled rotary table according to the present invention;

FIG. 3 is a disassembled side-by-side projection view of the rotational positioning accuracy and repositioning accuracy detecting portion of the numerically controlled rotary table of the system for detecting comprehensive performance of the numerically controlled rotary table according to the present invention;

FIG. 4 is a disassembled axial projection view of the vibration detection part of the numerically controlled rotary table of the system for detecting the comprehensive performance of the numerically controlled rotary table according to the present invention;

FIG. 5 is a disassembled axial projection view of the oil pressure detection part of the numerically controlled rotary table of the system for detecting the comprehensive performance of the numerically controlled rotary table according to the present invention;

FIG. 6 is a schematic wiring diagram of a voltage detection part of a motor of a numerically controlled rotary table of the system for detecting the comprehensive performance of the numerically controlled rotary table according to the present invention;

FIG. 7 is a schematic wiring diagram of the current detection part of the motor of the numerically controlled rotary table of the system for detecting the comprehensive performance of the numerically controlled rotary table according to the present invention

FIG. 8 is a structural schematic diagram of a control part of the system for detecting the comprehensive performance of the numerical control rotary table according to the present invention;

FIG. 9 is a flow chart of the method for testing the reliability of the numerically controlled rotary table according to the present invention.

Detailed Description

The invention is described in detail below with reference to the attached drawing figures:

embodiment 1 comprehensive performance detection system of numerical control rotary table

Referring to fig. 1 to 9, the present invention provides a system for detecting the comprehensive performance of a numerical control rotary table, which comprises: noise detection portion 2, positioning detection portion 3, vibration detection portion 4, oil pressure detection portion 5, turntable motor voltage detection portion 6, turntable motor current detection portion 7, signal processing unit:

the signal processing unit includes: a signal amplifier 81, a signal acquisition output device 82 and an upper server 83; the signal amplifier 81 is connected with the signal acquisition output device 82 through a cable; the signal acquisition output device 82 is connected to the upper server 83 by a cable.

The noise detection section 2 includes: a noise sensor 21, a first magnetic base 22;

the connecting rod of the noise sensor 21 is fixedly connected with the first magnetic base 22; the noise sensor 21 is connected to the signal amplifier 81 through a cable.

The positioning detecting section 3 is a laser interferometer including: a laser head 31, an angle interference mirror 32, a third magnetic base 33, a reflecting mirror 34 and a second magnetic base 35;

a fixing bracket 311 is arranged below the laser head 31;

the angle interference mirror 32 is fixed on a third magnetic base 33; the reflector 34 is fixed on the second magnetic base 35;

the transmitting end of the laser head 31 is aligned with the light path of the light inlet end of the interference mirror 32; the light-emitting end of the interference mirror 32 is aligned with the optical path of the reflector 34;

the laser head 31 is provided with a data transmission end; the data transmission terminal of the laser head 31 is connected to a signal amplifier 81.

The vibration detection part 4 is an acceleration sensor provided with a connecting seat and a vibration signal output end; the vibration signal output terminal is connected to the signal amplifier 81 through a cable.

The oil pressure detecting portion 5 includes: a connecting three-way pipe 51 and an oil pressure sensor 52;

the connecting three-way pipe 51 is a metal standard component; the connecting three-way pipe 51 is provided with a testing connecting pipe orifice, an oil outlet pipe connecting pipe orifice and a sensor connecting pipe orifice;

the sensor connecting pipe orifice is connected with an oil pressure sensor 52;

the oil pressure sensor 52 is provided with an oil pressure detection signal output end; the oil pressure detection signal output terminal is connected to the signal amplifier 81.

The turntable motor voltage detecting section 6 includes: a voltage transformer and a voltage transmitter;

the voltage transformer comprises: yellow (A phase) voltage transformer PT₁Green (B phase) voltage mutual inductor PT₂Red (C phase) voltage mutual inductor PT₃；

The yellow (A phase) voltage transformer PT₁Is provided with a primary side voltage detection connection terminal im₁And a primary side output terminal IN₁(ii) a Secondary side access terminal im₁(ii) a Secondary side connects outlet end IN₁；

The green (B phase) voltage transformer PT₂Is provided with primary side electricityPressure detection connecting end IIM₂And a primary side output terminal IIN₂(ii) a Secondary side access terminal IIm₂(ii) a Secondary side connection output end IIn₂；

The red (C phase) voltage transformer PT₃Is provided with a primary side voltage detection connection terminal IIIM₃And a primary side output terminal IIIN₃(ii) a Secondary side access terminal IIIm₃(ii) a Secondary side connecting outlet IIIn₃；

The voltage transmitter comprises: yellow (A-phase) voltage transmitter XT₁Green (B phase) voltage transducer XT₂Voltage transducer XT for red (C phase)₃；

The yellow (A phase) voltage transducer XT₁The first voltage transmitter access end, the first voltage transmitter grounding end and the first voltage transmitter signal output end are arranged; first voltage transmitter access end and secondary side access end I m₁Connecting;

the green (B phase) voltage transducer XT₂The second voltage transmitter access end, the second voltage transmitter grounding end and the second voltage transmitter signal output end are arranged; second voltage transmitter access end and secondary side access end IIm₂Connecting;

the red (C phase) voltage transducer XT₃The third voltage transmitter access end, the third voltage transmitter grounding end and the third voltage transmitter signal output end are arranged; third voltage transmitter access end and secondary side access end IIIm₃Connecting;

the primary side output end IN₁Primary side output terminal IIN₂Primary side output terminal III N₃Secondary side connected out terminal IN₁Secondary side out terminal IIn₂Secondary side out terminal IIIn₃The grounding end of the first voltage transmitter, the grounding end of the second voltage transmitter and the grounding end of the third voltage transmitter are in collinear grounding; the first voltage transmitter signal output terminal, the second voltage transmitter signal output terminal, and the third voltage transmitter signal output terminal are connected to the signal amplifier 81 through cables.

the current transformer is a clamp type current transformer; it includes: yellow (A phase) current transformer CT₁Green (B phase) current mutual inductor CT₂Green (B phase) current mutual inductor CT₃；

The yellow (A phase) current transformer CT₁The first current transformer connecting end and the first current transformer grounding end are arranged;

the green (B phase) current transformer CT₂The second current transformer connecting end and a second current transformer grounding end are arranged;

the red (C phase) current transformer CT₃A third current transformer connecting end and a third current transformer grounding end are arranged;

the current transformer includes: yellow (A-phase) current transformer IT₁Green (B-phase) current transformer IT₂Green (B-phase) current transformer IT₃；

The yellow (A phase) current is transmitted to the converter IT₁A first current transformer connecting end, a first current transformer grounding end and a first current transformer signal output end are arranged;

the green (B phase) current transformer IT₂A second current transformer connecting end, a second current transformer grounding end and a second current transformer signal output end are arranged;

the red (C phase) current transformer IT₃A third current transformer connecting end, a third current transformer grounding end and a third current transformer signal output end are arranged;

the connecting end of the first current transformer is connected with the connecting end of the first current transducer through a cable; the connecting end of the second current transformer is connected with the connecting end of the second current transducer through a cable; the connecting end of the third current transformer is connected with the connecting end of the third current transducer through a cable; the grounding end of the first current transformer, the grounding end of the second current transformer, the grounding end of the third current transformer, the grounding end of the first current sending changer, the grounding end of the second current sending changer and the grounding end of the third current sending changer are in collinear grounding;

the signal output end of the first current transmitter, the signal output end of the second current transmitter and the signal output end of the third current transmitter are connected with a signal amplifier 81 through cables;

Embodiment 2 detection method of comprehensive performance detection system of numerical control rotary table

A detection method of a comprehensive performance detection system of a numerical control rotary worktable detects comprehensive performance parameters of the numerical control rotary worktable; the body of numerical control rotary worktable includes: the device comprises a ground flat iron 11, a numerical control rotary table 12, a simulation bearing part 13, a cutting force loading part 14 and a control part;

the numerical control rotary table 12, the simulation bearing part 13 and the cutting force loading part 14 are fixed on the ground flat iron 11; the control part is fixed on the side surface of the floor iron;

the control part comprises: a first control portion 15, a second control portion 16, a third control portion 17;

the second control part 16 is fixed on the upper end of the first control part 15; the first control portion 15 is fixed to the rear end of the third control portion 17.

See fig. 1-9; a detection method of a comprehensive performance detection system of a numerical control rotary table comprises the following steps: noise detection, positioning detection, vibration detection, oil pressure detection, motor voltage detection and motor current detection;

the noise detection is to fix the first magnetic base 22 on the ground flat iron 11 beside the numerical control rotary table 12 in a magnetic attraction manner; collecting and converting sound and environmental noise signals generated by the numerical control rotary table into electric signals through the noise sensor 21, and transmitting the electric signals to the signal amplifier 81; the signal amplifier 81 amplifies and filters the signal and transmits the signal to the signal acquisition and output device 82; the signal acquisition output equipment 82 transmits the signal to the upper server 83; the upper server 83 processes and displays the detected sound signal in real time.

The positioning detection is to fix the reflector 34 on the table-board of the numerical control rotary table 12 by magnetic attraction through the second magnetic base 35; the angle interference mirror 32 is fixed on the ground flat iron 11 through a third magnetic base 33 in a magnetic attraction manner; the laser head 31 is fixed on the ground flat iron 11 through a fixing bracket below the laser head; the light beam emitted by the laser head 31 is divided into two paths by the angle interference mirror 32 and is emitted to the reflecting mirror 34, and the light beam returned by the reflecting mirror 34 is emitted to the laser head 31 by the angle interference mirror 33; the laser data transmission port on the laser mirror 31 is connected with the signal amplifier 81 through a cable; the signal amplifier 81 amplifies and filters the signal and transmits the signal to the signal acquisition and output device 82; the signal acquisition output equipment 82 transmits the signal to the upper server 83; the upper server 83 processes and displays the detected angle data in real time.

During test measurement, the numerical control rotary table 12 rotates by an interval angle d along the clockwise direction, and the recorded angle reading a1 is the detection starting point; rotating the numerical control rotary table 12 by an angle 2d in the counterclockwise direction, and recording an angle reading b 1; the above step is repeated m =360/d times, i.e. the measurement is completed 1 turn counter clockwise, and the angle readings a1, a2, …, am and b1, b2, …, bm are recorded. N turns are measured in this way.

The clockwise measurement method is the same as the counter-clockwise measurement method described above.

The vibration detecting section 4 is an acceleration sensor 41; the acceleration sensor 41 is provided with a connecting seat and a vibration signal output end; the vibration signal output is connected to a signal amplifier 81.

The vibration detection is that four vibration detection measuring points are arranged on the table surface of the numerical control rotary table 12 (because the numerical control rotary table is in rigid connection with the numerical control machine, four vibration detection measuring points are arranged on the table surface of the numerical control rotary table 12); each detection measuring point magnetic fixed base is fixed with an acceleration sensor; the acceleration sensor is connected with the signal amplifier 81;

the four vibration detection measuring points are respectively as follows: a first vibration measuring point 411, a second vibration measuring point 412, a third vibration measuring point 413 and a fourth vibration measuring point 414;

performing force analysis, and arranging a vibration detection measuring point 411 at a position subjected to external load; the floating working platform slightly sinks under the action of the external load, namely the platform of the numerical control rotary working platform 12 at the position 180 degrees different from the vibration detection measuring point 411 slightly floats correspondingly, and the vibration detection measuring point 412 is arranged at the position; a vibration detection measuring point 413 and a vibration detection measuring point 414 are respectively arranged at the positions where the connecting line of the vibration detection measuring point 411 and the vibration detection measuring point 412 rotates 180 degrees along the central line of the rotary table;

during the test, after the preliminary preparations such as channel setting and vibration sensor calibration are completed, measurement is carried out when the numerical control rotary table 12 is in idle running or loading; the measurement signal is output by the acceleration sensor 41 and is transmitted to the upper server 83 through the signal amplifier 81 and the signal acquisition output device 82 for real-time processing and display, and finally, the circumferential, axial and radial real-time vibration data of the numerical control rotary table 12 under the real working condition is obtained;

the oil pressure detection is that a testing connection pipe orifice of the three-way pipe 51 is in threaded sealing connection with an oil inlet 122 of the numerical control rotary table, an oil outlet pipe connection pipe orifice of the connection three-way pipe 51 is in threaded sealing connection with an oil outlet pipe 171 of the hydraulic pump station and the cooling device 17, and the other end of the connection three-way pipe is in threaded sealing connection with the oil pressure sensor 52;

the hydraulic oil pressure directly acts on the pressure measuring diaphragm of the oil pressure sensor 52, so that the pressure measuring diaphragm generates micro displacement which is in direct proportion to the medium pressure, the resistance of the oil pressure sensor 52 changes, an electronic circuit detects the change, and then a standard signal corresponding to the pressure is converted and output, the signal amplifier 81 amplifies and filters the signal and transmits the signal to the signal acquisition and output device 82, and the signal acquisition and output device 82 converts an analog signal into a digital signal and transmits the digital signal to the upper server 83 for real-time processing and display.

The motor voltage detection is the detection of the voltage of a three-phase input cable of the turntable motor; during test and measurement, the voltage transformer PT₁Primary side voltage detecting connection terminal im₁Is connected with a yellow (A phase) power supply cable; voltage transformer PT₂Primary side voltage detecting connection terminal iim₂Is connected with a green (B phase) power supply cable; voltage transformer PT₃Primary side voltage detecting connection terminal IIIM₃Is connected with a red (C phase) power supply cable; the voltage transmitter transmits the isolation into a direct current analog signal to the signal amplifier 81; after the signal amplifier 81 amplifies the signal, the amplified signal is transmitted to the acquisition and output device 82, and the analog signal is converted into a digital signal, and is transmitted to the upper server 83 for real-time processing and display.

The motor current detection is the detection of the three-phase input cable current of the turntable motor; during the test, press from both sides the power supply cable who withstands the test in proper order through pincer type current transformer: a yellow (A phase) power supply cable, a green (B phase) power supply cable and a red (C phase) power supply cable; the current transducer isolates and transmits the original current signal into a direct current analog signal to be transmitted to the signal amplifier 81; after the signal amplifier 81 amplifies the signal, the amplified signal is transmitted to the acquisition and output device 82, and the analog signal is converted into a digital signal, and is transmitted to the upper server 83 for real-time processing and display.

Embodiment 3 method for testing reliability of numerical control rotary table

Referring to fig. 9, a method for testing the reliability of a numerical control rotary table; the method is carried out on the basis of the original numerical control rotary table reliability test bed and the comprehensive performance detection system, and comprises eight parts, namely reliability test preparation conditions, reliability evaluation index determination, sampling quantity determination and test time determination, comprehensive performance detection of the numerical control rotary table, reliability test of the numerical control rotary table, comprehensive performance detection of the numerical control rotary table, fault judgment, data recording, data processing, reliability modeling and the like;

the method for testing the reliability of the numerical control rotary table comprises the following steps:

1. preparation conditions for reliability test

The preparation conditions for the reliability test of the numerical control rotary worktable comprise the requirements of the test environment, the test sample, the test device and the tester;

1) and (3) test environment: the reliability test has the advantages that the environment temperature is +15 to +35 ℃ (290K to 308K), the working pressure is 187V to 242V, the relative humidity is 45 to 75 percent, and the atmospheric pressure is 86 to 106 kPa; the test must be performed under defined environmental conditions;

2. determining reliability evaluation index

In order to accurately evaluate and measure and verify the reliability of the numerical control rotary table, firstly, a reasonable reliability evaluation index needs to be determined; the Mean Time Between Failures (MTBF) reflects the time quality of the product and reflects the capability of the product to keep specified functions within specified time; the mean time to first failure MTTFF reflects the mean working time before the first failure of the product; the mean repair time MTTR reflects the mean repair time when the product is in a working state of transposition from a fault state; considering that the numerical control rotary table is a repairable complex electromechanical product, and is used as one of key functional parts of the numerical control machine tool, the numerical control rotary table needs to have higher reliability level and stronger fault repairing performance;

the reliability test method of the numerical control rotary worktable selects the mean fault interval working time MTBF, the mean first fault time MTTFF and the mean repair time MTTR as main reliability evaluation indexes; during actual test, other reliability indexes (such as reliability and the like) can be added according to the requirements of users as references for evaluating the reliability level of the numerical control rotary table;

3. determining the number of samples and the test time

1) Sampling scheme

Randomly extracting samples from qualified numerical control rotary table products, wherein the samples are not allowed to be subjected to any special treatment in quality; the sampling scheme is shown in table 1:

2) test time

In order to fully expose the faults of the product and accurately and reasonably reflect the reliability level of the product, the running time of the reliability test must be long enough; on the basis of the known fault information and reliability level of the existing numerical control rotary table, the reliability test time selected by the method is 3 times or more than that of the MTBF of the existing numerical control rotary table; when the early fault elimination test is carried out on the numerical control rotary table, the total test time is not less than 120 hours.

4. Comprehensive performance detection of numerical control rotary worktable

5. Reliability test of numerical control rotary table

The main contents of the reliability test of the numerical control rotary worktable comprise a rotary table no-load transposition test, a dynamic force loading test when the rotary table is static and a dynamic force loading test when the rotary table runs;

1) continuous index test

The continuous indexing test is a continuous indexing test which is carried out on the numerical control rotary table according to the specified indexing angle interval and the indexing direction under the condition of only bearing the weight load of a workpiece, and mainly verifies whether the numerical control rotary table can realize the preset function. (ii) a The weight of the simulated workpiece is 70% of the maximum bearing weight of the rotary table, and the angle interval and test time of indexing are also considered in the continuous indexing test. The accumulated test time of the no-load transposition test of the turntable accounts for about 10% of the total test time;

when the numerical control rotary worktable runs, abnormal screaming sound and impact sound are avoided, and the noise sound pressure level of the numerical control rotary worktable is not more than 76dB (A). In the test process, cooling conditions are carried out according to relevant regulations, noise detection, vibration detection, motor voltage detection, motor current detection and the like are carried out, and meanwhile, the oil temperature of a hydraulic system is monitored, so that the oil temperature is prevented from being too high.

c. and starting the test, and carrying out forward and reverse continuous sequential transposition of the brake mechanism loosening, transposition and locking by the numerical control rotary table according to the angle intervals and the sequence shown in the table 2.

2) Dynamic force loading test of turntable at rest

The dynamic force loading test of the turntable in a static state refers to a test for carrying out dynamic force loading on the numerical control rotary table by simulating a certain mean value, amplitude, force application angle and loading frequency of dynamic cutting force under the locking state of the numerical control rotary table. The amplitude, the mean value, the angle and the frequency of the dynamic cutting force subjected to the simulated loading are divided into 2 large groups, each large group can be divided into 4 small groups of 6Hz, 15Hz, 21Hz and 35Hz according to the loading frequency, and the proportion of the cycle times of the dynamic force loaded by each small group is shown in tables 3 and 4; the accumulated test time of the dynamic force loading test of the numerical control rotary table when the numerical control rotary table is static is not less than 30 percent of the total test time;

when the numerical control rotary worktable operates, abnormal screaming sound and impact sound are avoided, and the noise sound pressure level of the numerical control rotary worktable is not more than 76dB (A); in the test process, cooling conditions are carried out according to relevant regulations, noise detection, motor voltage detection, motor current detection and the like are carried out, and meanwhile, the oil temperature of a hydraulic system is monitored to prevent the oil temperature from being too high;

c. the test is started, the numerical control rotary table is operated to 0 degree and locked, then the numerical control rotary table is loaded in an electro-hydraulic servo loading mode according to the loading schemes of the tables 3 and 4, the ratio of the amplitude value/the maximum value in the tables 3 and 4 is the ratio of the amplitude value of the simulated loading dynamic force to the maximum load capable of being borne by the numerical control rotary table, the ratio of the mean value/the maximum value in the tables 3 and 4 is the ratio of the mean value of the simulated loading dynamic force to the maximum load capable of being borne by the numerical control rotary table, and the tables 3 and 4 are eight-order program loading spectrums of the numerical control rotary table with different loading angles and loading frequencies respectively.

Impact should be avoided when dynamic forces are applied; before changing the loading angle or frequency, the numerical control rotary table needs to be controlled to rotate 45 degrees in sequence, and then loading is carried out;

3) dynamic force loading test during operation of rotary table

The dynamic force loading test during the operation of the rotary table refers to a test for carrying out dynamic force loading on the numerical control rotary table by simulating a certain mean value, amplitude, force application angle and loading frequency of dynamic cutting force under the condition that the numerical control rotary table continuously operates at a certain rotating speed; the amplitude, mean value, angle and frequency scheme of the dynamic cutting force of the simulation loading is the same as that of the dynamic force loading test when the rotary table is static. The numerical control rotary table in the dynamic force loading test during the operation of the rotary table needs to continuously operate at the rotating speed of 5-10 r/min, and the accumulated test time of the dynamic force loading test during the idle operation of the numerical control rotary table is not less than 50% of the total test time;

when the numerical control rotary worktable operates, abnormal screaming sound and impact sound are avoided, and the noise sound pressure level of the numerical control rotary worktable is not more than 76dB (A); in the test process, cooling conditions are carried out according to relevant regulations, noise detection, motor voltage detection, motor current detection and the like are carried out, and meanwhile, the oil temperature of a hydraulic system is monitored, so that the oil temperature is prevented from being too high.

The dynamic force loading test during the operation of the rotary table is carried out according to the following steps:

6. comprehensive performance detection of numerical control rotary worktable

7. Failure determination and data recording

1) Failure determination

Faults occurring on the numerical control rotary worktable are divided into associated faults and non-associated faults; the associated faults are caused by the quality defects of the product, and must be counted when explaining test or operation results or calculating reliability values; the non-related faults are caused by misuse or improper maintenance and external factors, and faults which are to be eliminated when explaining test or operation results or calculating reliability values are eliminated. Therefore, when the numerical control rotary worktable performs fault treatment and reliability modeling, only the associated fault is selected;

c. the numerical control rotary worktable has damaged states of loosening, breaking and the like of parts, structural members or components;

2) data recording

During the reliability test period of the numerical control rotary worktable, data should be effectively collected, analyzed and maintenance and change measures should be recorded in time. The recording of the content should include: numbering a numerical control rotary table; the start of the test period; time and test conditions of the occurrence of the fault; a fault phenomenon; the cause of the failure; classifying faults; corrective action taken; accumulating the test time and times; signing by a test attendant; maintenance time; filling a reliability operation record table (shown as a table 5) of the numerical control rotary table and a reliability laboratory test fault record table (shown as a table 6) of the numerical control rotary table;

8. data processing and reliability modeling

1) Reliability evaluation index observed value calculation

Suppose thatnThe number of samples tested by the numerical control rotary worktable,m _iis as followsiThe accumulated working time of the rotary table is numerically controlled,r _iis as followsiThe accumulated failure number of the numerical control rotary working table,Nif the total accumulated faults of the numerical control rotary table are total, the observed value of the Mean Time Between Failures (MTBF) is as follows:

the observed value of the mean time to first failure MTTFF is:

in the formula:m _iis as followsiThe working time before the first fault of the numerical control rotary working table.

The observed values for mean time to repair MTTR are:

2) Reliability modeling

The reliability modeling process is illustrated by taking an objective function as the Mean Time Between Failures (MTBF) as an example. The continuous non-fault working time of the numerical control rotary worktable is counted through data processingTiCalculating a reliability function R (t) Fault rate functionλ(t) Mean Time Between Failure (MTBF). Selecting reasonable distribution (such as two-parameter Weibull distribution) to fit fault probability density function curvefAnd (t) carrying out parameter solution by a parameter estimation method such as a simulated annealing algorithm and the like, carrying out K-S inspection on the obtained distribution model, and determining the distribution rule of the objective function if the distribution model passes the inspection.

The method comprises the following specific steps:

a. calculating a reliability function R (t) and a fault rate function lambda (t) of the numerical control rotary table:

wherein, the cumulative failure probability function F (t) =1-R (t).

b. Calculating Mean Time Between Failures (MTBF):

the probability density function of the two-parameter weibull distribution is:

d. performing K-S test on the target function distribution model, and if the test statistic Dn value is smaller than a critical value Dn, a, accepting the original hypothesis; otherwise, rejecting. And further obtaining the distribution rule of the target function.

Claims

1. A reliability test method for a numerical control rotary table is characterized in that a comprehensive performance detection system for the numerical control rotary table is adopted, and the method is operated according to the following steps:

(I) preparation conditions for the test

a. And (3) test environment: the environment temperature of the reliability test is +15 to +35 ℃, the working pressure is 187 to 242V, the relative humidity is 45 to 75 percent, and the atmospheric pressure is 86 to 106 kPa; the test must be performed under defined environmental conditions;

b. test samples: the test samples in the reliability test should have qualified performance and functions, the test samples which leave the factory should have the certification of qualified ex-factory inspection, the test samples should be new products or products produced under the condition of meeting the normal production, meanwhile, the test samples should be used according to the normal working condition, and all the test samples are numbered before the test;

c. the test device comprises: the test equipment, the detection instrument and the instrument of the reliability test are required to be identified to meet the relevant requirements, and the numerical control rotary table test device is required to be installed and debugged according to the regulations before the test;

d. the test personnel: a designated special person is responsible for organization and facilities of the reliability laboratory test of the numerical control rotary table, the responsibilities of a tester, a maintainer and a fault analysis person are determined, and the duty arrangement, the test diary and the fault maintenance form are ready;

(II) determining reliability evaluation index

Firstly, determining a reasonable reliability evaluation index; the Mean Time Between Failures (MTBF) reflects the time quality of the product and reflects the capability of the product to keep functions within the specified time; the mean time to first failure MTTFF reflects the mean working time before the first failure of the product; the mean repair time MTTR reflects the mean repair time when the product is in a working state of transposition from a fault state; considering that the numerical control rotary table is a repairable complex electromechanical product, and is used as a key functional component of the numerical control machine tool, the numerical control rotary table needs to have higher reliability level and stronger repair performance;

the reliability test method of the numerical control rotary worktable selects the mean fault interval working time MTBF, the mean first fault time MTTFF and the mean repair time MTTR as main reliability evaluation indexes; during actual test, adding other reliability indexes as references for evaluating the reliability level of the numerical control rotary table according to user requirements;

(III) determining sampling quantity and test time

1) Sampling scheme

Randomly extracting samples from qualified numerical control rotary table products, wherein the samples are not allowed to be subjected to any special treatment in quality; if the early fault elimination test is carried out, the whole number test is adopted; if a reliability bench test is carried out, the number of samples is determined according to the annual output which is less than or equal to 10, the number of the extracted samples is 1-2, the annual output is 10-100, the number of the extracted samples is 3-5, the annual output is more than 100, the number of the extracted samples is 5%, and the total number of general samples is not more than 10;

2) test time

(IV) detecting comprehensive performance of numerical control rotary worktable

Respectively carrying out comprehensive performance detection such as noise detection, positioning detection, vibration detection, oil pressure detection, motor voltage detection, motor current detection and the like on the numerical control rotary table, and recording specific values or ranges of each performance parameter of the numerical control rotary table in detail;

(V) reliability test of numerical control rotary table

1) Turntable no-load rotation test

The no-load transposition test needs to consider the transposition angle interval and the test time; the accumulated test time of the no-load transposition test of the numerical control rotary worktable accounts for 10 percent of the total test time;

in the no-load transposition test process, the comprehensive performance detection of noise detection, vibration detection, motor voltage detection and motor current detection is required to be carried out on the numerical control rotary table;

c. starting a test, and carrying out forward and reverse continuous sequential transposition of the brake mechanism loosening, transposition and locking on the numerical control rotary table according to the following angle intervals and sequence;

d)0° 60° 120° 180° 240° 300° 360° 300° 240° 180° 120° 60° 0°；

2) dynamic force loading test of turntable at rest

The amplitude, the mean value, the angle and the frequency of the dynamic force loading are divided into 2 large groups, each large group can be divided into 4 small groups of 6Hz, 15Hz, 21Hz and 35Hz according to the loading frequency, and the proportion of the dynamic force cycle number loaded by each small group is shown in tables 3 and 4; the accumulated test time of the dynamic force loading test when the numerical control rotary working table is in idle rest is not less than 30% of the total test time;

in the dynamic force loading test process when the rotary table is static, the comprehensive performance detection such as noise detection, motor voltage detection, motor current detection and the like needs to be carried out on the numerical control rotary table;

c. starting a test, operating the numerical control rotary table to 0 degree and locking, then loading the numerical control rotary table in an electro-hydraulic servo loading mode according to the loading schemes of the tables 3 and 4, and avoiding impact when applying dynamic force; before changing the loading angle or frequency, the numerical control rotary table needs to be controlled to rotate 45 degrees in sequence, and then loading is carried out; tables 3 and 4 are eight-order program loading spectrums of the numerical control rotary table with different loading angles and loading frequencies respectively;

；

3) dynamic force loading test during operation of rotary table

The amplitude, mean value, angle and frequency scheme of the dynamic cutting force for simulating loading is the same as that of a dynamic force loading test when the rotary table is static;

the numerical control rotary table continuously operates at the rotating speed of 5-10 r/min in the dynamic force loading test when the rotary table operates, and the accumulated test time of the dynamic force loading test when the numerical control rotary table operates accounts for not less than 50% of the total test time;

c. starting a test, controlling the numerical control rotary table to continuously run at a rotating speed of 5-10 r/min, and then carrying out dynamic force loading on the numerical control rotary table in an electro-hydraulic servo loading mode according to the loading schemes in the tables 3 and 4, wherein impact is avoided when dynamic force is applied;

before changing the loading angle or frequency, the numerical control rotary table needs to be controlled to rotate 45 degrees in sequence, and then loading is carried out;

(VI) detecting comprehensive performance of numerical control rotary worktable

Respectively carrying out noise detection, positioning detection, vibration detection, oil pressure detection, motor voltage detection and motor current detection comprehensive performance detection on the numerical control rotary worktable, recording specific values or ranges of each performance parameter of the numerical control rotary worktable in detail, and carrying out comparative analysis on each performance parameter of the numerical control rotary worktable detected in the step (four);

(VII) failure determination and data recording

1) Failure determination

a, losing one or more functions of a numerical control rotary table or a part of the numerical control rotary table;

2) data recording

During the reliability test period of the numerical control rotary worktable, data should be effectively collected, analyzed and maintenance and change measures should be recorded in time;

the recording of the content should include: numbering a numerical control rotary table; the start of the test period; time and test conditions of the occurrence of the fault; a fault phenomenon; the cause of the failure; classifying faults; corrective action taken; accumulating the test time and times; signing by a test attendant; maintenance time; filling a numerical control rotary table reliability operation record table, a numerical control rotary table reliability laboratory test fault record table and a numerical control rotary table reliability laboratory test report table;

(VIII) data processing and reliability modeling

1) Reliability evaluation index observed value calculation

the observed value of the mean time to first failure MTTFF is:

the observed values for mean time to repair MTTR are:

in the formula: mRj is the accumulated repair time of the jth numerically controlled rotary table; the accumulated failure number of the jth numerical control rotary worktable of the rj;

2) reliability modeling

The reliability modeling process is explained by taking an objective function as mean fault interval working time MTBF; counting the continuous non-fault working time Ti of the numerical control rotary table through data processing, and calculating a reliability function R (t), a fault rate function lambda (t) and mean fault interval working time MTBF; fitting a fault probability density function curve f (t) by using two parameters of Weibull distribution, performing parameter solution by using a simulated annealing algorithm, and performing K-S inspection on the obtained distribution model so as to determine the distribution rule of the target function;

the method comprises the following specific steps:

in the formula: cumulative failure probability function f (t) =1-r (t);

b. calculating Mean Time Between Failures (MTBF):

the probability density function of the two-parameter weibull distribution is:

in the formula, the dimension parameter is a shape parameter;

c. performing K-S test on the target function distribution model, and if the test statistic Dn value is smaller than a critical value Dn, a, accepting the original hypothesis; otherwise, rejecting; further obtaining the distribution rule of the target function;

a numerical control rotary table comprehensive properties detecting system, it includes: noise detection part (2), location detection part (3), vibration detection part (4), oil pressure detection part (5), revolving stage motor voltage detection part (6), revolving stage motor current detection part (7), signal processing unit: the method is characterized in that: the signal processing unit includes: the system comprises a signal amplifier (81), signal acquisition and output equipment (82) and an upper server (83); the signal amplifier (81) is connected with the signal acquisition output equipment (82) through a cable; the signal acquisition output equipment (82) is connected with the upper server (83) through a cable;

the noise detection section (2) includes: a noise sensor (21), a first magnetic base (22); the connecting rod of the noise sensor (21) is fixedly connected with the first magnetic base (22); the noise sensor (21) is connected with the signal amplifier (81) through a cable;

the positioning detection section (3) includes: the laser head (31), the angle interference mirror (32), the third magnetic base (33), the reflecting mirror (34) and the second magnetic base (35); a fixed bracket (311) is also arranged below the laser head (31); the angle interference mirror (32) is fixed on the third magnetic base (33); the reflector (34) is fixed on the second magnetic base (35); the laser head (31) is provided with a data transmission end; the data transmission end of the laser head (31) is connected with a signal amplifier (81);

the vibration detection part (4) is an acceleration sensor; the acceleration sensor is provided with a connecting seat and a vibration signal output end; the vibration signal output end is connected with a signal amplifier (81) through a cable;

the oil pressure detecting portion (5) includes: a connecting three-way pipe (51) and an oil pressure sensor (52); the connecting three-way pipe (51) is provided with a testing connecting pipe orifice, an oil outlet pipe connecting pipe orifice and a sensor connecting pipe orifice; the sensor connecting pipe orifice is connected with an oil pressure sensor (52); an oil pressure detection signal output end is arranged on the oil pressure sensor (52); the oil pressure detection signal output end is connected with a signal amplifier (81);

the turntable motor voltage detection section (6) includes: a voltage transformer and a voltage transmitter; the voltage transformer is connected with the voltage transmitter; the voltage transmitter is connected with the signal amplifier (81);

the turntable motor current detection section (7) includes: a current transformer and a current transformer; the current transformer is connected with the current transformer; the voltage transmitter is connected with a signal amplifier (81).

2. The numerical control rotary table reliability test method according to claim 1, characterized in that: a permanent magnet is arranged in a connecting seat at the lower ends of a first magnetic base (22), a second magnetic base (33) and a third magnetic base (35) of the comprehensive performance detection system of the numerical control rotary table.

3. The numerical control rotary table reliability test method according to claim 2, characterized in that: the turntable motor voltage detection part (6) of the comprehensive performance detection system of the numerical control rotary table comprises: a voltage transformer and a voltage transmitter; the voltage transformer is divided into: an A phase voltage transformer, a B phase voltage transformer and a C phase voltage transformer;

a primary side voltage detection connection end I, a primary side output end I, a secondary side input end I and a secondary side output end I are arranged on the primary side of the A-phase voltage transformer PT 1;

a primary side voltage detection connecting end II, a primary side output end II, a secondary side input end II and a secondary side output end II are arranged on the primary side of the B phase voltage transformer;

a primary side voltage detection connecting end III, a primary side output end III, a secondary side input end III and a secondary side output end III are arranged on the primary side of the C-phase voltage transformer;

the voltage transformer is divided into: an A phase voltage transmitter, a B phase voltage transmitter and a C phase voltage transmitter;

the A-phase voltage transmitter is provided with a first voltage transmitter access end, a first voltage transmitter grounding end and a first voltage transmitter signal output end; the first voltage transmitter access end is connected with the secondary side access end I;

the B phase voltage transmitter is provided with a second voltage transmitter access end, a second voltage transmitter grounding end and a second voltage transmitter signal output end; the second voltage transmitter access end is connected with the secondary side access end II;

the C-phase voltage transmitter is provided with a third voltage transmitter access end, a third voltage transmitter grounding end and a third voltage transmitter signal output end; the third voltage transmitter access end is connected with the secondary side access end III;

the primary side output end I, the primary side output end II, the primary side output end III, the secondary side output end I, the secondary side output end II, the secondary side output end III, the first voltage transmitter grounding end, the second voltage transmitter grounding end and the third voltage transmitter grounding end are in collinear grounding; the first voltage transmitter signal output end, the second voltage transmitter signal output end and the third voltage transmitter signal output end are connected with a signal amplifier (81) through cables.

4. The numerical control rotary table reliability test method according to claim 3, characterized in that: the turntable motor current detection part (7) of the comprehensive performance detection system of the numerical control rotary table comprises: a current transformer and a current transformer;

the current transformer is a clamp type current transformer; it includes: the phase-A current transformer, the phase-B current transformer and the phase-B current transformer are connected in series;

the A-phase current transformer is provided with a first current transformer connecting end and a first current transformer grounding end;

the phase B current transformer is provided with a second current transformer connecting end and a second current transformer grounding end;

the C-phase current transformer is provided with a third current transformer connecting end and a third current transformer grounding end;

an A-phase current transformer, a B-phase current transformer, and a B-phase current transformer;

the A-phase current transformer is provided with a first current transformer connecting end, a first current transformer grounding end and a first current transformer signal output end;

the B-phase current transformer is provided with a second current transformer connecting end, a second current transformer grounding end and a second current transformer signal output end;

the C-phase current transformer is provided with a third current transformer connecting end, a third current transformer grounding end and a third current transformer signal output end;

the first current transformer signal output terminal, the second current transformer signal output terminal and the third current transformer signal output terminal are connected to a signal amplifier (81) through cables.

5. The numerical control rotary table reliability test method according to claim 1, 2, 3 or 4, characterized in that: in the noise detection of the comprehensive performance detection system of the numerical control rotary table, during test measurement, the numerical control rotary table (12) rotates by an interval angle d along the clockwise direction, and a recorded angle reading a1 is a detection starting point; rotating the numerical control rotary table (12) by an angle 2d along the counterclockwise direction, and recording an angle reading b 1; completing the measurement of 1 turn counterclockwise, recording the angle readings a1, a2, …, am and b1, b2, …, bm, m =360/d times;

measuring n circles according to the method;

the upper computer calculates the error value of each detection interval relative to the detection starting point according to the provisions of the numerical control machine detection standard GB-17421.2-2000, and then calculates the rotation positioning precision and the repeated positioning precision of the numerical control rotary table (12) according to the standard.